Respuesta :
Answer:
Option D is the correct answer.
Step-by-step explanation:
Let x be the one way distance and t be the time out.
Time taken for back = t-1
We have plane's average speed out was 300 mph and average speed on the way back was 350 mph.
That is
[tex]\frac{x}{300}=t\texttt{ and }\frac{x}{350}=t-1[/tex]
Dividing both equations
[tex]\frac{\frac{x}{300}}{\frac{x}{350}}=\frac{t}{t-1}\\\\350t-350=300t\\\\t=7\texttt{ hours}[/tex]
Time taken for back = t-1 = 7-1 = 6 hours.
Total time taken = 7 + 6 = 13 hours
Option D is the correct answer.